This disclosure is in the field of signal communications to and from tools located within an oil or gas pipeline. More specifically, this disclosure relates to signal communications to and from these tools when in an interior space of a carbon steel or steel pipe or vessel using high speed radio frequency protocols.
High speed radio frequency communication—such as, but not limited to, Bluetooth, IEEE 802.15.4, WIFI, Xbee, Zigbee, Z-Wave, or their equivalents—are incapable of communicating across metallic boundaries such as a pipeline wall where the field is predominately electric and the Faraday Effect is significant. This inability creates significant issues which necessitate other more expensive technologies be employed when attempting a path of communication from the outside of the pipeline into the inner perimeter of the pipeline and, inversely, from the inside of the pipeline out to exterior receivers or repeaters.
Currently, low frequency communication is used. A low frequency approach requires a lot of power to drive the signal and make it through the wall of a carbon steel or steel pipeline. In many cases, the tool must be include a significant battery pack capability or a tethered power source, making the system relatively large and expensive. For example, signal frequencies may be about 20 Hz transmitting about 40 bits or so at a time. The low frequency approach is also fraught with issues relative to material cover of the pipeline that can and does limit the ability to transmit data. These transmission issues can worsen due to the amount of inherent moisture, groundwater and the soil depth, all of which can attenuate the signal. All of this creates significant hurdles when attempting to communicate with inline tools, tapping and plugging equipment, and pigging bodies.